The title character, an ex-slave, doesn’t kill all the white people. In fact, his best friend and co-hero is a white, European dentist turned bounty hunter played by Christoph Waltz, who won an Oscar as the dapper but terrifying Nazi colonel in Inglourious Basterds. Moreover, one of the chief villains of Django is played, in a surprise, by Samuel L. Jackson as a house slave who despises Django with a fury that makes him a perfect match for the wicked plantation owner (Leonardo DiCaprio) for whom he works.

Mostly, the movie is an incredibly violent, incredibly long, and often very funny popcorn picture with its roots in both spaghetti Westerns of the 1960s and blaxploitation movies of the 1970s. The quintessentially Tarantino moment comes when racist whites seeking to kill Django and his dentist friend form a posse of rough riders with bags over their heads (presaging the Ku Klux Klan) in 1858. The vigilante group (including former Miami Vice star Don Johnson as an easily outsmarted plantation boss and Jonah Hill in a cameo) falls into squabbling over a dispute about the craftsmanship of the bags. It’s a hilarious disquisition reminiscent of the argument about Madonna in Reservoir Dogs or the details of dining at a French McDonald’s in Pulp Fiction.

Other scenes in the movie may remind you of Butch Cassidy and the Sundance Kid or The Searchers, but the closest resemblance is to.... Blazing Saddles. Just as Gene Wilder and Cleavon Little joined forces as equals and shocked racists in Mel Brooks’ 1972 comedy (which was co-written by Richard Pryor), Waltz and Foxx make for a fine pair of gunslingers who don’t care what haters think of their friendship. They wander the South getting in and out of trouble as they search for Django’s wife (Kerry Washington), who is being tortured at the evil plantation run by Calvin Candie (DiCaprio). Django, a former slave, has received his freedom and a new job as bounty hunter courtesy of King Schultz (Waltz), who needs Django’s help in recognizing three men whom Schultz will receive a hefty fee for killing.

To the extent the movie invites controversy, it will do so for its wall-to-wall use of the N-word, and perhaps some will say it trivializes slavery by turning it into the backdrop for ridiculously bloody killing sprees and explosions. Slavery is still a sensitive subject that very few Hollywood filmmakers dare to explore; even Steven Spielberg’s Lincoln largely leaves out the details of the horror. But Tarantino’s purpose is to shame slavery by bringing it out into the light to mock it and show its practitioners meeting a cruel end. He has a lot of fun with his subject along the way, and most audience members probably will too.

But still, there’s a vague sense that Tarantino is coasting; there’s a been-there, shot-that feel to the whole thing. Once again the movie runs long; again there’s a massively violent climax; again there is a distracting and somewhat unfortunate attempt by the director to show he can act (this time he plays an Australian miner); again there are lots of appearances from forgotten B-movie and TV character actors (in addition to Don Johnson, Bruce Dern, Dennis Christopher, Tom Wopat and Russ Tamblyn show up); again there are visual quotations from classic movies.

We get it: Tarantino has seen a lot of films. Has he ever read a book, though? By the time Steven Spielberg and Woody Allen were Tarantino’s age, they rightly began to suspect they were repeating themselves, and began venturing into new territory. Spielberg filmed Schindler’s List when he was only 46; Tarantino will turn 50 next spring.

Are we expecting too much of Tarantino? Maybe. He does write clever and surprising dialogue, his characters are lively, and he always gets superb performances from his actors. His action scenes are entertainingly over the top. If Tarantino never really outgrew the comic books-and-cowboys stage of adolescence, he certainly fits the profile of millions in his generation. But at some point the sense that Tarantino is wandering through the halls of film history stealing bits and pieces and mashing them together is going to go stale. A couple of more movies like Django Unchained and moviegoers will start to wonder whether Tarantino has any original ideas or whether he’s just a spoof act -- the big-screen equivalent of Weird Al Yankovic.